Patents by Inventor Yuui Shimizu

Yuui Shimizu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20110215836
    Abstract: According to one embodiment, a clamp transistor is inserted in series between a P-channel field effect transistor and an N-channel field effect transistor and an intermediate level between a high potential supplied to a source of the P-channel field effect transistor and a low potential supplied to a source of the N-channel field effect transistor is input into a gate of the clamp transistor to clamp a drain potential of the N-channel field effect transistor.
    Type: Application
    Filed: March 4, 2011
    Publication date: September 8, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Yuui SHIMIZU
  • Patent number: 7965555
    Abstract: A non-volatile semiconductor memory device including: a NAND string having multiple memory cells connected in series and first and second select gate transistors disposed on the both ends; word lines coupled to the memory cells; and first and second select gate lines coupled to the first and second select gate transistors, wherein a data read mode is defined by the following bias condition: a selected word line is applied with a read voltage; one adjacent to the selected word line within first unselected word lines disposed on the first select gate line side is applied with a first read pass voltage while the others are applied with a second read pass voltage lower than the first read pass voltage; and second unselected word lines disposed on the second select gate line side are applied with a third read pass voltage higher than the first read voltage.
    Type: Grant
    Filed: February 2, 2009
    Date of Patent: June 21, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuko Namiki, Takuya Futatsuyama, Yuui Shimizu
  • Publication number: 20110128768
    Abstract: According to one embodiment, a differential circuit receives, as differential inputs, a readout signal read out from a semiconductor storage element and a reference voltage. An equalizing circuit controls, taking into account a state of a past input signal output from the differential circuit, the potential of the present differential signal output from the differential circuit. A sense amplifier detects a state of the differential signal output from the equalizing circuit. A state holding circuit holds a past state of the differential signal detected by the sense amplifier and supplies the state to the equalizing circuit.
    Type: Application
    Filed: September 17, 2010
    Publication date: June 2, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Yuui SHIMIZU
  • Publication number: 20110074494
    Abstract: A semiconductor device, a semiconductor memory tester, and a multi-chip package are provided. The semiconductor device includes a plurality of nonvolatile semiconductor memories; a boosting circuit which generates a boosted voltage for operating the plurality of nonvolatile semiconductor memories; and a boosting circuit controller which controls the operation of the boosting circuit to generate the boosted voltage on the basis of an operation sequence of the plurality of nonvolatile semiconductor memories.
    Type: Application
    Filed: December 8, 2010
    Publication date: March 31, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuui Shimizu, Shigeo Ohshima, Mie Matsuo
  • Patent number: 7907446
    Abstract: This disclosure concerns a memory including cell blocks, wherein in a first write sequence for writing data to a first cell block, drivers write the data only to memory cells arranged in a form of a checkered flag among the memory cells included in the first cell block, in a second write sequence for writing the data from the first cell block to a second cell block, the drivers write the data to all memory cells connected to a word line selected in the second cell block, and when the data is read from the first cell block or at a time of data verification when data is written to the first cell block, the word line drivers simultaneously apply a read voltage to two adjacent word lines, and the sense amplifiers detects the data in the memory cells connected to the two word lines.
    Type: Grant
    Filed: November 7, 2008
    Date of Patent: March 15, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuui Shimizu, Toshiaki Edahiro
  • Patent number: 7869265
    Abstract: A magnetic random access memory includes a first interconnection extending to a first direction, a second interconnection extending to a second direction perpendicular to the first direction, a magnetoresistive effect element formed between the first and second interconnections, having one terminal connected to the first interconnection, includes a fixed layer, a recording layer and a nonmagnetic layer, a film thickness of the fixed layer being larger than that of the recording layer, and a width of the fixed layer being larger than that of the recording layer, and configured to reverse a magnetization direction in the recording layer by supplying a first electric current between the fixed layer and the recording layer, and a diode having one terminal connected to the other terminal of the magnetoresistive effect element, and the other terminal connected to the second interconnection, and configured to supply the first electric current in only one direction.
    Type: Grant
    Filed: February 5, 2008
    Date of Patent: January 11, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuui Shimizu, Tatsuya Kishi
  • Patent number: 7869240
    Abstract: A semiconductor device, a semiconductor memory tester, and a multi-chip package are provided. The semiconductor device includes a plurality of nonvolatile semiconductor memories; a boosting circuit which generates a boosted voltage for operating the plurality of nonvolatile semiconductor memories; and a boosting circuit controller which controls the operation of the boosting circuit to generate the boosted voltage on the basis of an operation sequence of the plurality of nonvolatile semiconductor memories.
    Type: Grant
    Filed: June 19, 2008
    Date of Patent: January 11, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuui Shimizu, Shigeo Ohshima, Mie Matsuo
  • Patent number: 7864563
    Abstract: A magnetic random access memory according to an example of the invention comprises a first reference bit line shared by first reference cells, a second reference bit line shared by second reference cells, a first driver-sinker to feed a first writing current, a second driver-sinker to feed a second writing current, and a control circuit which checks data stored in the first and second reference cells line by line, and executes writing simultaneously to all of the first and second reference cells by a uniaxial writing when the data is broken.
    Type: Grant
    Filed: September 28, 2007
    Date of Patent: January 4, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuui Shimizu, Tsuneo Inaba
  • Patent number: 7859881
    Abstract: A magnetic memory device includes a first magnetic line which has a plurality of cells made of magnetic domains partitioned by domain walls, and in which information is recorded in each cell, a first write element formed at one end portion of the first magnetic line, and a first read element formed at the other end portion of the first magnetic line.
    Type: Grant
    Filed: February 7, 2007
    Date of Patent: December 28, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshihisa Iwata, Katsuyuki Fujita, Yuui Shimizu
  • Patent number: 7835210
    Abstract: A magnetic random access memory includes a memory element having a first fixed layer, a first recording layer, and a first nonmagnetic layer, a first reference element having a second fixed layer, a second recording layer, and a second nonmagnetic layer, antiparallel data being written in the first reference element, a second reference element making a pair with the first reference element, and having a third fixed layer, a third recording layer, and a third nonmagnetic layer, parallel data being written in the second reference element, and a current source which, when a read operation is performed, supplies a current from the second fixed layer to the second recording layer in the first reference element, and supplies the current from the third recording layer to the third fixed layer in the second reference element.
    Type: Grant
    Filed: August 29, 2007
    Date of Patent: November 16, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuui Shimizu
  • Patent number: 7791919
    Abstract: A semiconductor memory device is configured to vertically stack a plurality of memory chips using a resistance-change memory element as a memory cell in one package. The memory chips each have first and second memory position detection pads connected via chip top and bottom electrodes facing each other. Of the vertically stacked memory chips, the lowermost memory chip is provided with the connected chip bottom electrodes of the first and second memory position detection pads. The memory chips each control the variable resistance element, and in a state that the first memory position detection pad has a higher resistance than the second memory position detection pad, compare a voltage applied to the first memory position detection pad with the chip position detection signal using the comparator when a voltage is applied between the first and second memory position detection pads provided on the uppermost layer memory chip.
    Type: Grant
    Filed: November 13, 2008
    Date of Patent: September 7, 2010
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Yuui Shimizu
  • Publication number: 20090238003
    Abstract: A non-volatile semiconductor memory device including: a NAND string having multiple memory cells connected in series and first and second select gate transistors disposed on the both ends; word lines coupled to the memory cells; and first and second select gate lines coupled to the first and second select gate transistors, wherein a data read mode is defined by the following bias condition: a selected word line is applied with a read voltage; one adjacent to the selected word line within first unselected word lines disposed on the first select gate line side is applied with a first read pass voltage while the others are applied with a second read pass voltage lower than the first read pass voltage; and second unselected word lines disposed on the second select gate line side are applied with a third read pass voltage higher than the first read voltage.
    Type: Application
    Filed: February 2, 2009
    Publication date: September 24, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yuko NAMIKI, Takuya Futatsuyama, Yuui Shimizu
  • Publication number: 20090135638
    Abstract: A semiconductor memory device is configured to vertically stack a plurality of memory chips using a resistance-change memory element as a memory cell in one package. The memory chips each have first and second memory position detection pads connected via chip top and bottom electrodes facing each other. Of the vertically stacked memory chips, the lowermost memory chip is provided with the connected chip bottom electrodes of the first and second memory position detection pads. The memory chips each control the variable resistance element, and in a state that the first memory position detection pad has a higher resistance than the second memory position detection pad, compare a voltage applied to the first memory position detection pad with the chip position detection signal using the comparator when a voltage is applied between the first and second memory position detection pads provided on the uppermost layer memory chip.
    Type: Application
    Filed: November 13, 2008
    Publication date: May 28, 2009
    Inventor: Yuui Shimizu
  • Publication number: 20090122611
    Abstract: This disclosure concerns a memory including cell blocks, wherein in a first write sequence for writing data to a first cell block, drivers write the data only to memory cells arranged in a form of a checkered flag among the memory cells included in the first cell block, in a second write sequence for writing the data from the first cell block to a second cell block, the drivers write the data to all memory cells connected to a word line selected in the second cell block, and when the data is read from the first cell block or at a time of data verification when data is written to the first cell block, the word line drivers simultaneously apply a read voltage to two adjacent word lines, and the sense amplifiers detects the data in the memory cells connected to the two word lines.
    Type: Application
    Filed: November 7, 2008
    Publication date: May 14, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuui SHIMIZU, Toshiaki EDAHIRO
  • Publication number: 20090067212
    Abstract: A magnetic random access memory includes a memory element having a first fixed layer, a first recording layer, and a first nonmagnetic layer, a first reference element having a second fixed layer, a second recording layer, and a second nonmagnetic layer, antiparallel data being written in the first reference element, a second reference element making a pair with the first reference element, and having a third fixed layer, a third recording layer, and a third nonmagnetic layer, parallel data being written in the second reference element, and a current source which, when a read operation is performed, supplies a current from the second fixed layer to the second recording layer in the first reference element, and supplies the current from the third recording layer to the third fixed layer in the second reference element.
    Type: Application
    Filed: August 29, 2007
    Publication date: March 12, 2009
    Inventor: Yuui SHIMIZU
  • Publication number: 20090003103
    Abstract: A semiconductor device, a semiconductor memory tester, and a multi-chip package are provided. The semiconductor device includes a plurality of nonvolatile semiconductor memories; a boosting circuit which generates a boosted voltage for operating the plurality of nonvolatile semiconductor memories; and a boosting circuit controller which controls the operation of the boosting circuit to generate the boosted voltage on the basis of an operation sequence of the plurality of nonvolatile semiconductor memories.
    Type: Application
    Filed: June 19, 2008
    Publication date: January 1, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yuui SHIMIZU, Shigeo Ohshima, Mie Matsuo
  • Publication number: 20080253173
    Abstract: A magnetic random access memory according to an example of the invention comprises a first reference bit line shared by first reference cells, a second reference bit line shared by second reference cells, a first driver-sinker to feed a first writing current, a second driver-sinker to feed a second writing current, and a control circuit which checks data stored in the first and second reference cells line by line, and executes writing simultaneously to all of the first and second reference cells by a uniaxial writing when the data is broken.
    Type: Application
    Filed: September 28, 2007
    Publication date: October 16, 2008
    Inventors: Yuui SHIMIZU, Tsuneo INABA
  • Publication number: 20080186759
    Abstract: A magnetic random access memory includes a first interconnection extending to a first direction, a second interconnection extending to a second direction perpendicular to the first direction, a magnetoresistive effect element formed between the first and second interconnections, having one terminal connected to the first interconnection, includes a fixed layer, a recording layer and a nonmagnetic layer, a film thickness of the fixed layer being larger than that of the recording layer, and a width of the fixed layer being larger than that of the recording layer, and configured to reverse a magnetization direction in the recording layer by supplying a first electric current between the fixed layer and the recording layer, and a diode having one terminal connected to the other terminal of the magnetoresistive effect element, and the other terminal connected to the second interconnection, and configured to supply the first electric current in only one direction.
    Type: Application
    Filed: February 5, 2008
    Publication date: August 7, 2008
    Inventors: Yuui SHIMIZU, Tatsuya Kishi
  • Publication number: 20080080234
    Abstract: A magnetic memory device includes a first magnetic line which has a plurality of cells made of magnetic domains partitioned by domain walls, and in which information is recorded in each cell, a first write element formed at one end portion of the first magnetic line, and a first read element formed at the other end portion of the first magnetic line.
    Type: Application
    Filed: February 7, 2007
    Publication date: April 3, 2008
    Inventors: Yoshihisa Iwata, Katsuyuki Fujita, Yuui Shimizu
  • Publication number: 20070258282
    Abstract: A magnetic memory device includes a magnetoresistance element which has first and second ends. First data is written into the magnetoresistance element by an electric current flowing from the first end to the second end. Second data is written into the magnetoresistance element by an electric current flowing from the second end to the first end. A first p-type MOSFET has one end connected to the first end. A second p-type MOSFET has one end connected to the second end. A first n-type MOSFET has one end connected to the first end. A second n-type MOSFET has one end connected to the second end. A current source circuit is connected to each another end of the first and second p-type MOSFETs and supplies an electric current. A current sink circuit is connected to each another end of the first and second n-type MOSFETs and draws an electric current.
    Type: Application
    Filed: March 7, 2007
    Publication date: November 8, 2007
    Inventors: Yoshihiro UEDA, Tsuneo Inaba, Yuui Shimizu, Kiyotaro Itagaki